Effects of nimodipine on the production of thromboxane A₂ following total global cerebral ischemia

To clarify the contribution of vasoconstrictor prostaglandins to the hypoperfusion state typically following total global cerebral ischemia, 14 mongrel dogs were subjected to 11 minutes of global cerebral ischemia. They were then randomly assigned to receive either no treatment or an intravenous bolus of the calcium channel blocker nimodipine, 10 μg/kg, 15 minuts after ischemia followed by a continuous infusion of nimodipine, 1.0 μg/kg/min. Thromboxane (Tx) A₂ production, as measured by cerebral venous levels of TxB₂ (the stable metabolite of TxA₂) increased similarly in the two groups. In contrast to previous studies, mean postischemic cerebral blood flow did not increase sufficiently in the nimodipine-treated group to achieve statistical significance. These data suggest that the improved neurological outcome associated with nimodipine treatment following global cerebral ischemia does not relate to reduced levels of the prostaglandin precursor arachidonate.